A polyoxyalkylene alkyl ether acetic acid such as a polyoxyethylene alkyl ether acetic acid is a polyoxyalkylene alkyl ether compound having an end substituted with a carboxylic acid, and it is known as a surfactant that may be used for cosmetics, an emulsifying agent, a solubilizing agent, a dispersant, a gelling agent, a cleansing base, or the like.
Properties of a polyoxyalkylene alkyl ether acetic acid can be adjusted by changing pH. As a polyoxyalkylene alkyl ether acetic acid has excellent resistance to hard water and an aqueous solution thereof is stable against various polyvalent metal ions such as calcium or aluminum and has a mild action on the skin, it is expected to be applied for various uses.
As a method for manufacturing a polyoxyalkylene alkyl ether acetic acid such as a polyoxyethylene alkyl ether acetic acid, a method of an organic chemical carboxymethylation of a terminal hydroxyl group of a polyoxyalkylene alkyl ether by reacting monochloroacetic acid to a polyoxyalkylene alkyl ether in the presence of a base such as sodium hydroxide is generally used [hereinbelow, referred to as “carboxymethylation”].
In JP-A 62-198641, a method for producing a salt of a polyoxyethylene alkyl ether acetic acid by dehydrogenating and oxidizing a polyoxyethylene alkyl ether in an aqueous solution using a noble metal catalyst in the presence of a base such as sodium hydroxide is disclosed [hereinbelow, referred to as “alkali neutralization oxidation”].
In JP-A 4-221339, a method for producing a polyoxyethylene alkyl ether acetic acid by dehydrogenating and oxidizing a polyoxyethylene alkyl ether using a noble metal catalyst in the absence of a base is disclosed [hereinbelow, referred to as “non-neutralization oxidation”].
U.S. Pat. No. 5,495,045 discloses production of an alkoxyalkyl carboxylic acid from an alkoxyalkanol in the presence of a cerium salt. JP-A 61-293948 discloses production of a carboxylic acid from a primary alcohol in the presence of a platinum catalyst. JP-B 2903187 discloses production of a polyoxyethylene alkyl ether acetic acid by oxygen-oxidization of R—O—(CH2CH2O)n-H in the presence of a catalyst containing platinum or palladium and bismuth or lead. JP-A 54-079229 discloses a method for oxidizing polyoxyethylene ether by oxygen-oxidization of R—O—(CH2CH2O)n-H in the presence of a platinum carbon catalyst.